How to read errors on Halscope

So I've been fiddling and learning how to use Halscope if you haven't seen my latest posts. And I'm a bit confused as to what I'm looking at and what I'm trying to get to happen through adjustment, other than tuning, that is. Of course the goal is to get the servo to tune to the point where there is an instantaneous move to ramp up, a flattening at it's top commanded speed, then a drop back to zero where it stops, all with the encoder counting the pulses and keeping up with the commanded position as closely as possible, so as to not overshoot and waver at either the beginning, middle or end. I understand the theory. But I'm trying to understand what exactly I'm trying to adjust and by how much, to make this happen accurately.

I understand that as you increase and decrease the gain on the trace that you're sourcing on Halscope, it changes the ability to see error. And I understand that this scale change translates to real world measurements as read through the encoder. I get that part, although not completely. But am I looking for the difference between the high and low points of the trace from it's horizontal starting line to determine the error the scale I'm tracing the signal from? Am I looking at the difference between how far apart the horizontal start line is from where it goes back to it's zero point? Because sometimes, the trace starts horizontally at one point,then it wavers and where it flattens, the trace is at another horizontal level, all together.

Maybe I'm not using the right terminology? Attached is the latest screenshot I'm getting with the calibration menu settings on the left.

Keep in mind, I'm a newbie. Even if there is a strong, vernacular, tutorial about the language I should use, that would be very helpful.

The trace of the following error on the scope is simply how far the encoder's feedback position differs from the commanded position. For a move in the positive direction, when the following error trace is above the 0 line it represents how far the encoder is lagging behind the commanded position, when the trace is below 0 it is ahead of the commanded potion.

In your tuning you are striving to minimize the following error. (Keep the trace as close to zero as possible all the time.)